NOUS40KWBC 131425
FOS/NOAAPORT NOTICE NO. 1742 JULY 13... 2000
ATTENTION FAMILY OF SERVICES SUBSCRIBERS/NOAAPORT USERS
SUBJECT NOTICE OF INTENT TO CHANGE AVN MOS GUIDANCE
EFFECTIVE WITH THE 1200 UTC FORECAST CYCLE ON JULY 18...2000...
GUIDANCE FOR CEILING HEIGHT AND TOTAL SKY COVER WILL BE
ADDED TO THE NEW AVN MOS MESSAGES. THESE MESSAGES ARE
IDENTIFIED WITH WMO HEADERS FOPA20... FOUS21-FOUS26... AND
FOAK37-FOAK39... AND ARE STORED AS MAV PRODUCTS IN THE AWIPS
TEXT DATA BASE. THE CEILING HEIGHT AND TOTAL SKY COVER
GUIDANCE PROVIDE FORECASTS OF CATEGORIES OF CEILING HEIGHT
AND SKY COVER VALID EVERY 3 HOURS FROM 6 TO 60 HOURS AFTER
0000 OR 1200 UTC AND AT THE 66- AND 72-H PROJECTIONS. THE
CATEGORICAL DEFINITIONS FOR CEILING HEIGHT ARE AS FOLLOWS
1 - LESS THAN 200 FT... 2 - 200 TO 400 FT... 3 - 500 TO 900
FT... 4 -1000 TO 3000 FT...
5 - 3100 TO 6500 FT... 6 - 6600 TO 12000 FT... AND 7 - GREATER
THAN 12000 FT OR UNLIMITED. THE CATEGORICAL DEFINITIONS FOR
TOTAL SKY COVER ARE AS FOLLOWS CL - CLEAR... SC - GREATER
THAN 0 TO 4 OCTAS OF TOTAL SKY COVER... BK - GREATER THAN 4
TO LESS THAN 8 OCTAS OF TOTAL SKY COVER... AND OV - 8 OCTAS OF
TOTAL SKY COVER. MORE DETAILS ON THE NEW GUIDANCE MAY BE
FOUND AT THE FOLLOWING
HTTP/COLON//WWW.NWS.NOAA.GOV/TDL/SYNOP/MOS2000.HTM
AT THE SAME TIME... EQUATIONS TO PREDICT THE CONDITIONAL
PROBABILITY OF PRECIPITATION TYPE /FREEZING... FROZEN... OR
LIQUID/ WILL ALSO BE IMPLEMENTED. GUIDANCE FOR PRECIPITATION
TYPE WILL NOT BE DISPLAYED ON THE MESSAGE UNTIL SEPTEMBER 1.
PRIOR TO THAT DATE... ANOTHER NOTICE WILL BE ISSUED WITH
APPROPRIATE DETAILS.
END
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